Cheats

Lewis and Clark
Enter "YOU GOT YOURSELF A FINE PAIR OF EYES" as a code phrase to unlock all areas.
Invincibility
Enter "HE GIVES STRENGTH TO THE WEAK" as a code phrase.
Infinite Dead Eye
Enter "I DON'T UNDERSTAND IMNFINITY" as a code phrase.
Infinite Ammo
Enter "ABUNDANCE IS EVERYWHERE" as a code phrase.
Gun Set 1
Enter "IT'S MY CONSTITUTIONAL RIGHT" as a code phrase to unlock some weapons.
Gun Set 2
Enter "I'M AN AMERICAN. I NEED GUNS" as a code phrase to get the buffalo rifle, sawed-off shotgun, semi-auto pistol, Schofield revolver, Winchester repeater, and fire bottle x3.
Decrease Bounty
Enter "THEY SELL SOULS CHEAP HERE" as a code phrase.
Diplomatic Immunity
Enter "I WISH I WORKED FOR UNCLE SAM" as a code phrase. You will now have no bounty/wanted level.
Good Guy
Enter "IT AINT PRIDE. IT'S HONOR" as a code phrase to have a good reputation.
Famous
Enter "I AM ONE OF THEM FAMOUS FELLAS" as a code phrase to become famous.
Money
Enter "THE ROOT OF ALL EVIL, WE THANK YOU!" as a code phrase to get $500.
Coach
Enter "NOW WHO PUT THAT THERE?" as a code phrase to spawn a coach.
Horse
Enter "BEASTS AND MAN TOGETHER" as a code phrase to spawn a horse.
Infinite Horse Stamina
Enter "MAKE HAY WHILE THE SUN SHINES" as a code phrase.
Gang Chic
Enter "YOU THINK YOU TOUGH, MISTER?" as a code phrase to unlock the Treasure Hunter Outfit.
Man In Uniform
Enter "I LOVE A MAN IN UNIFORM" as a code phrase to unlock the Bureau Uniform, U.S. Army Uniform, and U.S. Marshal Uniform.
Sharp Dressed Man
Enter "DON'T YOU LOOK FINE AND DANDY" as a code phrase to unlock the Gentlemen's Suit.
Jack Attack
Enter "OH MY SON, MY BLESSED SON" as a code phrase to change John into Jack, John's son.
Who?
Enter "HUMILITY BEFORE THE LORD" as a code phrase to become a nobody.
Hic
Enter "I'M DRUNK AS A SKUNK AND TWICE AS SMELLY" as a code phrase to become drunk.
Old School
Enter "THE OLD WAYS IS THE BEST WAYS" as a code phrase to enable the Sepia filter.
 Bonus